It is sometimes desirable to be able to sever a length of hermetically sealed tubing and to then be able to rejoin the severed tube ends to recreate the fluid communication within the tube, all without the loss of the hermetic seal.
One such situation is found in the manufacture of refrigeration equipment in which tubing systems are incorporated and charged with a refrigerant to provide the refrigerant circulation from the compressor-condenser to the evaporator coils of the refrigerator.
Typically, the components are located in the refrigerator cabinetry relatively remote from each other. It is highly desirable to be able to test the refrigeration system prior to installation into the refrigerator cabinetry, but this remote location of the system components renders it difficult to first assemble the refrigeration system and test for leaks, etc. and then assemble the refrigeration system into the refrigerator cabinetry. It would thus be desirable if the refrigeration system could first be assembled or tested, the tubing connecting the evaporator and compressor-condenser portion of the the system severed, the components assembled into the refrigerator cabinetry, and the severed ends rejoined without the need to recharge the system and with a high degree of assurance that the refrigeration system would function properly. Such severing and rejoining would of necessity be such that the seal would not be lost and the escape of refrigerant or the introduction of noncondensable gas, such as the atmospheric air, be prevented.
This process should also be carried out without the heating of the system to such an extent that the Freon, oil or other refrigerant be broken down into lighter constituents.
It has been heretofore known in the prior art to connect sealed lengths of tubing by means of an internal piercing element, which pierces a sealing membrane. These arrangements are presently incorporated with precharged tubing utilized in installing home air conditioning units. In these systems, the tubing ends to be connected to the evaporator and condenser coils, respectively, are charged with refrigerant with the ends of the tubing sealed by an internal diaphragm contained within the threaded coupling. Upon threading of the coupling into the corresponding fittings on the coils, a piercing element penetrates the membrane allowing the refrigerant charge to circulate through the tubing and the evaporator and condenser coils.
An example of this approach is disclosed in U.S. Pat. No. 2,933,333 to Bredtschneider et al.
While this approach has worked satisfactorily for such applications, it can be appreciated that this arrangement does not provide for an initial severing of the sealed tubing with a subsequent rejoining process. Furthermore, relatively costly fittings are required as well as an internal diaphragm seal. Cost being a crucial factor in the design of mass consumer appliances, such as refrigerators and freezers, the necessity for such prepared tube joint hardware is a significant drawback.
In U.S. Pat. No. 3,127,892 to Bellamy, Jr. et al, there is disclosed a relatively simple coupling arrangement in which a collapsible tube is utilized together with an internal piercing element to join two tube ends while the tubes remain sealed. However, that arrangement does not provide for the initial severing of the tube and furthermore does not disclose an arrangement for simply and effectively providing a joining of two sealed tube ends. Rather, the penetration by the piercing element is only with respect to a seal of one of the tubes which would not accommodate the application described above in which both severed ends would be sealed.
Another similar tube coupling arrangement with an internal seal piercing element is disclosed in U.S. Pat. No. 3,902,489 to Carter.
Both of these latter patents are disclosed in the context of blood processing or handling in which the seal is to prevent the introduction of contaminants but which is not adapted to the containment of a fluid under pressure. Rather, it is only to prevent the introduction of contaminants and the sealing arrangement and materials involved are not adaptable to pressure systems.
It is accordingly an object of the present invention to provide a method for severing a fluid pressure vessel such as hermetically sealed tubing without the loss of the seal to prevent the escape of fluid charge or the introduction of ambient air, and to further provide for rejoining of the severed ends and reestablishment of the fluid communication between the severed tube ends also without the loss of the seal.
It is another object of the present invention to provide such a method which can be carried out at relatively low cost without the need for preparing the tube ends or the use of tube fittings.
It is still another object of the present invention to provide a coupling for rejoining the severed tube ends according to the method of the present invention.